Background Renal biopsy is the gold standard for providing information about the histological classes of lupus nephritis and the degree of activity and chronicity in the glomeruli. Novel biomarkers are able to discriminate lupus renal activity and its severity, predict renal flares, and monitor treatment response and disease progress are clearly necessary.
Objectives evaluate the role of anti-nucleosome antibodies in lupus patients, its diagnostic and predictive value
Methods Group I, 40 SLE patients divided into: group I A (20 SLE patients with no renal disease), and group I B (20 SLE patients with lupus nephritis). Group II: 20 healthy subjects as control. SLEDAI and SLEDDI for the assessment of disease activity and damage. Serum anti-nucleosome antibodies titre was evaluated by ELISA.
Results For group IA 35% had mild disease activity, 35% had moderate and 30% had severe activity. For group IB, 20% had moderate disease activity and 80% had severe disease activity, with a statistical significant difference, p<0.001. In group IB 55% had organ damage. Renal biopsy was done for patients in group IB, 6 had class III lupus nephritis, 4 had class IV lupus nephritis,8 had combined class IV and V lupus nephritis. Patients had a pathological activity index 0-3/24, 5 patients had an activity index 4 -6/24, and 4 patients had an activity index 7-9/24. Four patients had chronicity index 0/12, 4 patients had a chronicity index 1/12, 5 patients had chronicity index 2/12, 3 patients had a chronicity index 4/12 and 1 patient had a chronicity index 6/12. Concerning serum Anti- nucleosome antibodies level, it was significantly higher in group I (A&B) (156.43±73.69) u/ml than in group II (6.50±1.85) u/ml, p<0.001. When comparing group IA and group IB, the mean value of serum anti-nucleosome antibodies in group IB was significantly higher than the mean value of group I (A), p<0.001. Roc curve of serum ant-inucleosome antibodies shows that serum anti-nucleosome antibodies can significantly discriminate between normal persons and SLE patient at cut off level >20u/ml. Also, Roc curve of serum ant-inucleosome antibodies shows that serum antinucleosome antibodies can significantly discriminate between lupus patients with and without lupus nephritis and SLE patient at cut off level >160u/ml as a diagnostic of renal involvement in SLE. there was a positive significant correlation between the serum level of anti-nucleosome antibodies and SLEDAI in the studied group of patients in group IA,
Conclusions Serum anti-nucleosome antibodies can significantly discriminate between normal and SLE patients with a very high sensitivity and specificity and can significantly discriminate between SLE patients with and without lupus nephritis. There is a significant correlation between serum level of anti-nucleosome antibodies and SLEDAI score and the activity index of renal biopsy.
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Disclosure of Interest None declared